In the sector, there are known containers with mobile bottom which, when coupled with airless pumps, allow the dispensing of a product contained in the container without the said product being contaminated by the air present in the external environment. Each time the pump is operated, part of the fluid is expelled and the bottom rises slightly, in order to compensate for the fall in volume due to the expulsion of the product dispensed by the pump.
One problem experienced with these containers concerns the filling which must be carried out before coupling the container to the pump.
For some fluid products, especially cosmetic or medical products, which must therefore be handled with considerable care, the filling step is critical since it must be carried out using appropriate systems within a controlled environment. In fact, most of these fluids must not come into contact with air or with contaminating environments.
To solve this problem, the filling step and the step consisting of coupling the pump to the container are carried out almost simultaneously and within the same controlled atmosphere environment. In this way, it is certain that there is no contamination of the fluid introduced into the container, since once the pump is coupled, the system is sealed and hermetic and can no longer be contaminated.
The methodology described above is effective but involves high costs and flexibility problems deriving from the need to provide controlled environments in which two essentially independent steps take place, namely that consisting of filling the container and that consisting of sealing (by means of the pump) the filled container.
FR2730708-A1 and FR2695111-A1 show valve systems which are applicable to a container where, instead of the mobile bottom, a deformable bag is envisaged. These solutions aim to seal off the container and the contents thereof immediately after the filling step, thereby allowing the pump to be coupled later on.
However, these solutions are not very effective, especially if coupled with containers with a mobile bottom, as they do not always guarantee good sealing off of the contents. In fact, the closure of the container after filling is performed by valves made of an elastic material (silicone, rubber, etc.) which do not guarantee a hermetic seal, especially if the filling pressure is not optimal (for example, when the container with a mobile bottom is only partially filled, i.e. with an amount of fluid which is lower than the maximum capacity).
Another problem encountered with the prior art is that the traditional top-fill valves described in the aforesaid patent documents do not envisage the provision, prior to filling, of a container with a mobile bottom from which the air has been removed (i.e. vacuum-sealed or depressurised).
In fact, when coupled to a depressurised container with a mobile bottom and placed in a room pressure environment, the commonly known valves would open, allowing the entry of (possibly contaminated) air into the said container.